def get_name_of_file_part(filename, part):
    filename, ext = os.path.splitext(filename)
    return '__{}_{}{}_part'.format(filename, part, ext)


def split_file_to_parts(filename, parts):
    part_size = os.path.getsize(filename) / parts
    with open(filename, 'rb') as init_file:
        for part in range(parts):
            with open('%s%s' % (FILE, part), 'wb') as file_part:
                file_part.write(init_file.read(part_size))